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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: Soft Upgrade and Downgrade
Date Wed, 22 Mar 2006 16:42:30 GMT
Oystein Grovlen - Sun Norway wrote:

> I agree that soft upgrade has a value, but I think you give soft
> upgrade credit for things that are actual not provided by soft upgrade.
Just a few somewhat disjointed but relevant thoughts  before I sign off
of this discussion for a while, because I need to fix some bugs.

First of all I want to say that there is a great dependence on soft
upgrade in the installed user base so if the community decided to
deprecate soft upgrade (which I am strongly against) it would need to be
just that a deprecation and some solution to the current usage models
would need to be found in advance.   So this is not a 10.2 discussion. 

But a few things to think about.

Many applications  have their own soft upgrade model where they allow
you to downgrade if there was an issue with the upgrade.    If  we take
the example of the email client that is moving from  Derby 10.0 to Derby
10.3,  they cannot implement their own soft upgrade if we do not
provide  that capability in Derby.

In the application server environment there is a a tangled web of  Derby
versions.  Many applications test and ship with one Derby version and
end up running in an application server with with another.   We do not
yet support loading multiple derby versions in the same JVM, so the
applications are all tied together.

 Sometimes there are scenarios where two JVM's will access the database
at different times, for instance an IDE running at one version accesses
the database and then it is used in the  application server  environment.

In terms of being able to revert, I am not so worried about corruption
by the new version.  I am worried about application compatibility.  

But like I said not a 10.2 discussion. Let's pick it back up next
release when there is less time crunch.


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